Motor drive control apparatus

Abstract

A motor drive control apparatus for driving and controlling a linear vibration motor having a mover supported by a spring, with an AC current. The motor drive control apparatus includes a waveform creation unit for creating a comparative current waveform to be a reference of a driving current for the linear vibration motor based on the operating condition of the linear vibration motor, a current detector for detecting the driving current, and a controller for controlling a driving voltage of the linear vibration motor so that a difference between the comparative current waveform and a waveform of the current detected by the current detector becomes zero. The frequency of the driving current is controlled to be close to the resonance frequency of the linear vibration motor, based on the comparative current waveform. Accordingly, the driving frequency of the linear vibration motor can always be brought to the resonance frequency without using a sensor for detecting a displacement, speed, or acceleration of the mover, for example.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to a motor drive control apparatus and, more particularly, to a motor drive control apparatus for controlling a linear vibration motor on the basis of its driving current, thereby to drive the motor with high efficiency.BACKGROUND ART[0002]Conventionally, linear motors have been used as sources of reciprocating vibrations (refer to Japanese Published Patent Application No. Hei.2-52692 (FIG. 1)). This literature discloses a linear motor for generating a reciprocating vibration (hereinafter referred to as a linear vibration motor).[0003]The linear vibration motor is constructed as a single-phase sync motor having a mover comprising a rod-shaped permanent magnet, and a stator comprising an electromagnet. The electromagnet is obtained by winding a coil around both ends of a U-shaped iron core.[0004]An output voltage from an AC power supply is converted into a full-wave rectified voltage having a frequency twice as high ...

AI Technical Summary

Benefits of technology

[0010]The present invention is made to solve the above-described problems. Therefore, an object of the present invention to provide a motor drive control apparatus which can efficiently drive a linear vibration motor at a resonance frequency or a frequency close to the resonance frequency, regardless of load fluctuations, without using a sensor for detecting displacement, speed, or acceleration of a mover of the linear vibration motor.

[0011]According to a first aspect of the present invention, a motor drive control apparatus is provided for driving and controlling a linear vibration motor having a stator and a mover, where the mover is supported by a spring so as to form a spring vibration system including the mover. This apparatus comprises: a voltage output unit for outputting an AC driving voltage to the linear vibration motor; a current detector for detecting a driving current supplied to the linear vibration motor; a current waveform creation unit for creating a first AC current waveform to be a reference of the driving current, on the basis of the operating conditions of the linear vibration motor; and a controller for controlling the driving voltage of the linear vibration motor which is output from the voltage output unit, so as to reduce a difference between the first AC current waveform and a second AC current waveform which is a result of detection by the current detector. The controller adjusts a frequency of the AC driving current to be close to a resonance driving frequency of the linear vibration motor, according to the first AC current waveform. Therefore, the driving frequency of the linear vibration motor can always be brought to the resonance frequency or a frequency close to the resonance frequency, without using a position sensor for detecting the position of the mover or the like.

[0012]Thereby, drive control for driving the linear vibration motor can be realized with high efficiency regardless of load fluctuations, without the necessity of incorporating a sensor, which undesirably leads to an increase in size of the linear vibration motor, and unnecessary restrictions such as securing operation reliability of the sensor.

Problems solved by technology

Thereby, drive control for driving the linear vibration motor can be realized with high efficiency regardless of load fluctuations, without the necessity of incorporating a sensor, which undesirably leads to an increase in size of the linear vibration motor, and unnecessary restrictions such as securing operation reliability of the sensor.

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